DE 10 2005 007 301 A1 discloses a switch in which a moving contact piece is arranged in a cuboid housing and rests on a stationary contact piece when the switch is closed. The current flows via the two contact pieces, which are disconnected by means of a switching toggle in order to open the switch. The arc which is struck in the process is quenched with the aid of quenching plates which are arranged in the area of the contact pieces. The arc produces a high gas overpressure, which is dissipated externally through a vent opening in the housing side wall. In order to prevent these gases from re-entering, the vent opening is provided with a curvature or direction change.
In other known switch disconnectors, the contact pieces are arranged at the free ends of a contact lever which can pivot and is often referred to as a double lever. In the case of a multipole switch, one contact lever is in each case provided for each phase. All of the contact levers are pivoted jointly by way of one switching shaft in order to interrupt the current, with their contact pieces being disconnected from one another.
This has the disadvantage that the vent opening must be arranged directly behind the quenching plates if they are intended to support the magnetic attraction force of the plates by means of the gas flow. It is therefore located close to the rear face of the switch, thus resulting in a risk of electrical flashover to the rear wall.